diff options
| author | Chris Metcalf <cmetcalf@tilera.com> | 2013-02-01 12:37:48 -0500 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@tilera.com> | 2013-03-22 15:47:00 -0400 |
| commit | adf6d9b30f089c52e674e84ca2960581e504e5e3 (patch) | |
| tree | f680f2877480201116e54da1e6a1af848884d646 /arch/tile/include | |
| parent | ef567f25d5d9d803b89bc2aec6bb71fe8b4bebd9 (diff) | |
tile: support atomic64_dec_if_positive()
Use the normal cmpxchg() idiom to implement this functionality.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Diffstat (limited to 'arch/tile/include')
| -rw-r--r-- | arch/tile/include/asm/atomic.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/tile/include/asm/atomic.h b/arch/tile/include/asm/atomic.h index f2461429a4a..e71387ab20c 100644 --- a/arch/tile/include/asm/atomic.h +++ b/arch/tile/include/asm/atomic.h @@ -131,4 +131,25 @@ static inline int atomic_read(const atomic_t *v) #include <asm/atomic_64.h> #endif +#ifndef __ASSEMBLY__ + +static inline long long atomic64_dec_if_positive(atomic64_t *v) +{ + long long c, old, dec; + + c = atomic64_read(v); + for (;;) { + dec = c - 1; + if (unlikely(dec < 0)) + break; + old = atomic64_cmpxchg((v), c, dec); + if (likely(old == c)) + break; + c = old; + } + return dec; +} + +#endif /* __ASSEMBLY__ */ + #endif /* _ASM_TILE_ATOMIC_H */ |